The BIOS on this board default setting is “auto” to detect PCI-e slot speed between Gen 1, Gen 2, Gen 3. Please manual setting M/B BIOS to Gen 1 because ARC-1200 is a Gen 1 card. This unstable situation is happening on speed changing when M/B adjusts PCI-e speed to detect card on each slot.
Tags: ARC-1200, BIOS, reboot